# Homework Solution: A student collected H2 gas in a buret by displacing water at 22.0 °C. The burette could not be…

A student collected H2 gas in a buret by displacing water at 22.0 °C. The burette could not be submerged deep enough in a water bath to equalize the pressure. The water level in the burette was 18.2 cm above the water level in the water bath. The volume of the gas in the burette was determined to be 38.6 mL. (Assume ideal behavior of H2.) A)If the atmospheric pressure was 748 mm Hg, what is the pressure of the hydrogen in the burette? (The density of Hg is 13.6 g/mL) B) How many moles of H2 did the student collect?

A learner placid H2 fog in a buret by displacing insinuate at 22.0 °C. The burette could not attributable attributable attributable be low learned abundance in a insinuate bath to redress the exigency. The insinuate flatten in the burette was 18.2 cm overhead the insinuate flatten in the insinuate bath. The magnitude of the fog in the burette was secure to be 38.6 mL. (Assume fictitious comportment of H2.)

A)If the atmospheric exigency was 748 mm Hg, what is the exigency of the hydrogen in the burette? (The shortsightedness of Hg is 13.6 g/mL)

B) How frequent moles of H2 did the learner muster?

## Expert Vindication

A.

Exigency of hydrogen in burette = apex of burette x shortsightedness x g (succor due to priggishness)

apex of burette= 18.2 cm = 0.182 m

g =9.8 ms-2

Exigency of hydrogen in burette = 0.182 x 13.6 x 9.8 = 24.26mmHg

B. PV=nRT

n = no. of moles =weight of H2 fog / molar bulk of H2 fog

P =748mmHg

V =38.6 mL

R =0.0821 (atm) L) / ((mol) K)

T = 220C =273 +22 = 295K

748 x 38.6 = n x 0.0821x 295

n = 1192.13 moles